This invention relates to bar clamps of the type designed to be operated by one hand to ratchet a movable jaw carrier along the bar toward a fixed jaw, with provision for releasing the movable jaw carrier.
A well-known type of bar clamp in the prior art is designed to be operated by one hand, while the other hand holds the work to be clamped between the fixed and movable jaw of the bar clamp. In most cases the jaws are opened wider than the work to be clamped, and it they are too wide, much time is wasted in ratcheting the movable jaw along the bar with the handle provided for this purpose. This is especially the case when repetitively clamping objects of varying dimensions, since the tendency is to set the movable jaw with a generous opening, so that it doesn""t have to be corrected if the opening is too small. The only other alternative is to resort to using both hands, which is difficult if one hand is needed to hold the objects to be clamped.
Accordingly, one object of the invention is to provide an improved bar clamp of the type described above, which can be quickly set to the correct position to begin clamping.
Another object of the invention is to provide an improved bar clamp of the type described that can be set up with one hand.
Briefly stated the invention comprises an improvement to a bar clamp of the type having a bar, a fixed jaw disposed on the bar, and a movable jaw arranged to slide along the bar to and from said fixed jaw, said movable jaw adapted in a known manner to be operated with one hand and having an advancing means arranged to ratchet the movable jaw step-wise toward the fixed jaw and a holding means with a release mechanism arranged to prevent the movable jaw from moving away from the advanced position until released by the release mechanism, said bar clamp being known in the prior art, the improvement comprising an abutment member disposed on the bar on the side of the movable jaw opposite that of the fixed jaw, and a spring member disposed along the bar between the abutment member and the movable jaw and arranged to create a force biasing the movable jaw toward the fixed jaw.